An investigation to characterize the effect of entrainment in a confined jet impingement arrangement is presented. The investigated configuration models an impingement cooled turbine blade passage and holds two staggered rows of inclined impingement jets. In order to distinctly promote thermal entrainment phenomena the jets were heated separately. A steady-state liquid crystal technique was used to obtain near-wall fluid temperature distributions for the impingement surfaces at adiabatic conditions. Additionally, flow field measurements were undertaken using Particle Image Velocimetry (PIV). Furthermore, compressible RANS simulations were carried out with ANSYS CFX using Menter’s SST turbulence model to accompany the experiments. Distributions of effectiveness, velocity, and turbulent kinetic energy detail the complexity of the aerothermal situation. The study was conducted for a jet Reynolds number range from 10,000 to 45,000.
The experimental and numerical results are generally in good agreement. Nevertheless, the simulations predict flow features in particular regions of the geometry that are not as prominent in the experiments. These affect the effectiveness distributions, locally. The investigations revealed that the effectiveness is independent of the temperature difference between the heated and cold jet as well as the jet Reynolds number.